function initPlaceHolders() {
	if('placeholder' in document.createElement('input')) { //如果浏览器原生支持placeholder
		return;
	}

	function target(e) {
		var e = e || window.event;
		return e.target || e.srcElement;
	};

	function _getEmptyHintEl(el) {
		var hintEl = el.hintEl;
		return hintEl && g(hintEl);
	};

	function blurFn(e) {
		var el = target(e);
		if(!el || el.tagName != 'INPUT' && el.tagName != 'TEXTAREA') return; //IE下，onfocusin会在div等元素触发
		var emptyHintEl = el.__emptyHintEl;
		if(emptyHintEl) {
			//clearTimeout(el.__placeholderTimer||0);
			//el.__placeholderTimer=setTimeout(function(){//在360浏览器下，autocomplete会先blur再change
			if(el.value) emptyHintEl.style.display = 'none';
			else emptyHintEl.style.display = '';
			//},600);
		}
	};

	function focusFn(e) {
		var el = target(e);
		if(!el || el.tagName != 'INPUT' && el.tagName != 'TEXTAREA') return; //IE下，onfocusin会在div等元素触发
		var emptyHintEl = el.__emptyHintEl;
		if(emptyHintEl) {
			//clearTimeout(el.__placeholderTimer||0);
			emptyHintEl.style.display = 'none';
		}
	};
	if(document.addEventListener) { //ie
		document.addEventListener('focus', focusFn, true);
		document.addEventListener('blur', blurFn, true);
	} else {
		document.attachEvent('onfocusin', focusFn);
		document.attachEvent('onfocusout', blurFn);
	}

	var elss = [document.getElementsByTagName('input'), document.getElementsByTagName('textarea')];
	for(var n = 0; n < 2; n++) {
		var els = elss[n];
		for(var i = 0; i < els.length; i++) {
			var el = els[i];
			var placeholder = el.getAttribute('placeholder'),
				emptyHintEl = el.__emptyHintEl;
			if(placeholder && !emptyHintEl) {
				emptyHintEl = document.createElement('span');
				emptyHintEl.innerHTML = placeholder;
				emptyHintEl.className = 'emptyhint';
				emptyHintEl.onclick = function(el) {
					return function() {
						try {
							el.focus();
						} catch(ex) {}
					}
				}(el);
				if(el.value) emptyHintEl.style.display = 'none';
				el.parentNode.insertBefore(emptyHintEl, el);
				el.__emptyHintEl = emptyHintEl;
			}
		}
	}
}

initPlaceHolders();